Vacuum chuck jigs



Jan. 3, 1956 J. WALLACE ET AL 2,729,040

VACUUM CHUCK JICs Filed Feb. 1o, 1954 JAMES WALLACE NORLIN O. LEWIS INVEN TORS ATTORN EY United States Patent Marietta, Gat assignqrs toBoeingY Airplane, Company, Wichita, Kans a cOrinrratiml of?` DelawareApplication February 1`0, 195,4, Serial No. 409,479

5 Claims. (Cl. 51235) rlfhis invention relates to vacuum chuck jigs orthe like for ixedly holding items of sheet-form, or` other work, whilevarious operations are performed thereon.

Devices of this general character have long been used, for instance, inthe plate glass industry for fixedly holding plane glass sheets duringpolishing operations. Apparatus of uthis kind, havinga permanently andpredeterminedly curved work-supporting surface, has also been proposedfor use in repetition manufacture where the sanding or polishing ofsheet material is required, But l(he prior art does not provide a deviceas characterized wherein different predetermined curvatures of aworkholding and sustaining surface can be produced; and it is the'priinary object ofvthis invention tofdo so.

j Thus the present invention contemplates primarily the provision of`avacuum chuck or jig having a work-holding and sustaining surface whichvc an be readily adjusted'arnd sustained to conform` to the surfacecntour of a particular piece of work, a heayy gauge pre-contoured,airplane wing skin for example, so as to "securely hold same'while itsends are trimmed or milled or other operations performed.

' More specili'cally the invention contemplates in a device of thischaracter the use of a spring metal chuckcarryipg plate which is somounted and acted upon by adjustable means that it can be caused toassume a wide variety of different curyature-incorporating contoursaccording to the contour of the surface of the work to be supported.

It is `also an aim of the invention to provide a device for the purposeindicated which is of simple, strong and durable construction,comparatively inexpensive to manufnture'a-nd requifresvno special skillto operate. The invention also resides in cer-tain novel features of,construct-ion, combination and arrangement of the various parts and in-rnodes of operation, as -will be understood and appreciated by thoseversed in the art upon reference to the now preferred example of theinyention shown the accompanying drawing in connection wit-h `theIdetailed description thereof to follow.

'ln the drawing, wherein the `same reference .charac- .ters designatethe same` .parts :throughout .the several :vier/vs.- v

Figure 1 is a side elevational View fpantly broken and oartlfyin section@t one af the unitsemh Vas my rinvention, fit .being slated that severalO f Same in lateral spesevmay he used .to support the airplane uWinsskip `or otbe r-.wqrk;

.Figure .2 xis ,a sectional view taken on .the .line .of .Eiaure 31,;

,Figure ,3 ,is .apQrSneti-ve View partlybt011-ar1 partly .in sectionshowing one Of the vacuum Chucks- Referring vto ,the drawing 'byreference characters, numera'l 5 indicates a heavy base plate havingsecured thereto at opposite ,ends the Ushaped brackets 6, 8,respectively. `Bloths =7 -secure the bracket 6 -to the plate 5 -wh'ilebolts 9 perform uthe same function vas to bracket 8,

'These brackets f6, 8 `have -the 'spaced Aupsta-nding arms FPlce 2v6a,r8a,l respectively, and such arms pivotally support the opposite endsof a, flexible and elongated chuck-carrying steel platre 10. This plate10 is adapted to be adjusted to, and sustained, in differentarchnformcontours by means of a series of basecanrried j ack screws tobe referred'to here! inafter.l Y v i i In carrying out the invention,one end of the exible steel plate lll'has welded or otherwise securedtheret'g the sleeve 1'1 through which extends the pin 12 Vwhoseen'tlsare pivoted in the upper'portions of the bracket arms'G. The other endof the exible chuck-carrying steel'pla'te 10 is pivotally supported bythe head of a 'T-bolt '14, there being sleeve elements 13 welded Iorotherwise xedly secured to"sad plate end at opposite sides of the'lf-bolt stem 14a, as. suggested in Fig. 1l The ends of the T-bolt head14 extend, beyond the outer ends of theA sleeve elements 13 to beguidingly retained inthe aligned andge'n'- erally horizontal slots v15which areformed in the Yope posite arms 8g of the Ubr acket 8. i A

The stemI 14a of the Tfbolt 14 is threaded 14b, as indicated in Fig. 1,and slidably projects throughv an un# threaded guide hole 17 in thecross bar I6. This cross bar 16 is welded tothe opposed inner surfacesof 'bracket arrns 8a adjacent the rear top portions thereof, also asshown in Fig'. 1, *I

The threaded guide stem 14a of the slidably mounted T--bolt 14 hasthreaded upon its outer portionan adjustable nut or wheel 1S whose hubportion 181 is'adapted tobear against the outer surface of said crossbar "16 as shown in Fig. 1. Thus the adjustablemountingof the sleevedend 13`of the flexible steel plate 10 and'the`piv`- otal mounting l2 ofits opposite end functions with'the jack screws 19 to enable said plateto be adjusted to,

v and rigidly supported in, a number of dilferent arch-formconformations when viewed in edge elevation as in l. Turning now to thejack screws 19, it will be noted -from an inspection of Fig. 1 that theyare arranged in spaced series lengthwise of the base plate Scand vtheflexible steel plate 10 which they support.

rl`he jack screws 19 and associated elements being duplicates of oneanother, a description of one assembly will suffice. i c Y As shown inFig. l, each jack screw 19 is provided at its upper end lwith axedlyattached and preferably metal sustaining pad 20 which isengageable'with the underside of the flexible plate 10. The uppersurface of each jack pad 20 is provided with ainotch 26A (Fing. 2) toclear the chuck anchoring studs or screws 28.

The lower end of each jack screw 19 is slidably received in the centralbore 22a of a bearing member 22, whose lower end 22b is received in aholel 24 in the base pla-te 5. The bearing member 22 has acircumferential outstanding ange 23 which is supported upon the f'psurface .of the base plate 5, land screws 25 engaging ang'e 23 areprovided to vsecure the bearing member Z2 to the base plate 5. Threadedupon each jack screw 19 is a conventional elevating nut 26 whose hub 26abears against the .upper end of the bearing 22 so that when said nut 26is turned 2in one direction the jack screw will be actuated upwardly.When the nut 26 is turned in the other direction fthe relatedjack'screw19 will be forced downwardly into the bearing 22 through the action ofthe flexible steel plate 10, anditsload. 'i

Incidental reference has been made earlier herein to -the `work-engagingchucks 27 which are shown in tvFig. -l `as carried by the flexible steelplate V10 in longitudinal series with an intervening space between eachchuck.

`One of these chucks 27 is illustrated in vperspective on an enlargedscale in Fig, 3, while lFig. -2 illustrates one lof said chucks in endelevation, the work and the flexible steel plate 10 being shown in crosssection.

ln further carrying out the invention, I provide each chuck 217 with adepending lange 27a at each side to engage the proximate side edge ofthe llexible steel plate 1t) as indicate-d in Fig. 2 so as to preventshifting of said chucks transversely of plate 1?. The respective chucks27 aresecured to the flexible Steel plate l@ against longitudinalshifting by means of headed screws 28 which extend through said llexibleplate l from the under surface thereof and into tapped holes 29 in saidchucks 27 as indicated in Fig. l. The flanges 27a extend below thenether surface of the plate and receive the jack pads between them. Thellanges 27a thus serve to prevent lateral movement of the jack pads, asclearly shown in Fig. 2.

The chucks 27 are of the vacuum-operated variety and detailed referenceto same will now be made, referring particularly to the disclosure inFig. 3 As shown, the chucks 27 are square although they may, of coursebe otherwise shaped. ln the illustrated embodiment of the chuck 27,opposite sides of the top portion provide the raised work-supportingllanges 3d. These work-supporting ilanges 3b parallel the dependingspring-plate-engaging flanges 27a and are spaced outwardly from theendless top surface groove 31 which receives the vacuum sealing member32.

The vacuum sealing member 32, which is of rubber or the like, providesthe outwardly projecting wall and its widened base makes a snug tit inthe chuck groove 31. The narrowed and flexible work-contacting outerportion 32a of the vacuum-retaining wall 32 projects, as shown, wellbeyond the plane of the work-engaging side flanges of said chuck. Thus,the space between the work-engaging llanges 3i) and the flexiblevacuumre taining Wall portions 32a enables the latter to flex outwardlywhen forced into engagement with the work 41 so that the latter will besupported by the sustaining side llanges 3) of the chuck as indicated inFig. 2.

Fig. 3 also illustrates that the chuck 27 has a central upwardlyprojecting rectangular boss 33 whose outer wall provides the inner wallof the vacuum wall-receiving groove 31. The outer end of the boss 33terminates well short of the plane of the outer edges of thework-sustaining side flanges 30.

The waffle iron-like appearance of the outer end of the central boss 33is produced by the intersecting air passage grooves 33a, 33b, whichcommunicate with the vacuum-retaining wall 32 and with the central, andpreferably shallow, clover form vacuum recess 34 in the outer end ofsaid boss 33. The bottom 34a of the clover form recess 31 willpreferably be substantially in plane with the bottoms of boss grooves33a, 33b, as shown.

The bottom of what might be termed one leaf of the clover form recess 34has the inwardly extending vacuum passage hole 35, the lower end 35a ofwhich communicates with the vacuum passage 36. The vacuum passage 36leads outwardly through one side of the chuck 27 and terminates in thethreaded counterbore 37 for connection to the conventional suction line33 which is indicated in Fig. 1.

The vacuum hole 35, 35a is shouldered adjacent passage portion 35a tosupport a layer of glass fiber or other filter material 4t) whichprevents foreign matter from getting into vacuum line This iiltermaterial is held in place by a screen-like grid 33 which is frictionallyheld in the enlarged inlet portion of hole 35 and seats on a shoulder asshown.

The suction opening or hole 35, 35:1 to the recess 34, while shown in aleaf formation of the clover form recess at one side, may be otherwiselocated and of course recess 34 may be of different shape. It will beunderstood that the intersecting surface grooves or passages 33a, 3319,of the waffle iron-like outer end of the boss 33 provide for thewithdrawal of air from adjacent each of the vacuurn-retaining wallportions to the clover form vacuum recess, as heretofore noted.

The operation of the device will doubtless be understood from theforegoing description, but can be summarized as follows:

The heavy gauge airplane wing skin or other work 41 which has beenpre-contoured is disposed upon the chucks of two or more laterallyspaced units such as is shown in Fig. l. Then the jack screw nuts 26 areadjusted so that the jack screws 19 cause the llexible steel plate 1t)to substantially conform to the bottom work surface with thevacuum-retaining chuck wall portions 32a making firm and uniform contactwith the work 41. When necessary the shiftable pivot 14 will be adjustedby moving the stop nut 13 inwardly or outwardly in reference to thecross bar 16 which is carried by the bracket arms 8a.

When the vacuum retaining wall ends 32a all make proper contact with theunder surface of the wing or other work 41, the line 38 is put undervacuum to exhaust air from the space enclosed by said vacuum walls 32,32a. This causes the work-sustaining walls 30 to be drawn intosupporting engagement with the undersurface of the work 4l, the flexibleouter portions 32a of the rubber vacuum retaining walls ilexing to admitof this action. The work is firmly held during trimming or cuttingoperations and is readily released by relief of the vacuum in the line38.

Having thus described the invention, what is claimed is:

l. In a multiple vacuum chuck holder or the like, the combination of abase, a superjacent tlexible Work load sustaining carrier member, aseries of work retaining vacuum chuck members detachably mounted on saidcarrier member, each of said chuck members having depending side llangesembracing opposite edges of said carrier member, bracket means pivotallysupporting opposite ends of said carrier member and carried by saidbase, means operable to effect longitudinal adjustment of one end ofsaid carrier member relatively of said base, upstanding jacks carried bysaid base and extending in a series lengthwise of said base and carriermember, carrier member engaging and sustaining heads ixedly secured tothe upper ends of the respective jacks for varying the attitude of thecarrier member, and a vacuum line having connection with said chuckmembers for electing the grip of the latter to the work.

2. In a multiple vacuum chuck holder or the like, the combination of abase, a superjacent ilexible work load sustaining carrier member, aseries of work retaining vacuum chuck members carried in longitudinalseries upon the upper face of said carrier member, base carried meanspivotally supporting opposite ends of said carrier member, meansassociated with one end of said carrier member and its base carriedmeans for effecting longitudinal adjustment of said carrier member end,and an upstanding and deformable base carried supporting means for saidcarrier member and arranged lengthwise of the latter, and a vacuum linehaving connection with said chuck members for etfecting the grip of thelatter to the work.

3. The combination set forth in claim 2, in which said chuck members aredetachably secured to said carrier member and have depending sidellanges embracing side edges of the carrier member.

4. In a multiple vacuum chuck holder or the like, the

'combination of a base, a superjacent flexible work load sustainingcarrier member, a series 0f work retaining vacuum chuck membersdetachably mounted on said carrier member, each of said chuck membershaving depending side ilanges embracing opposite edges of said carriermember, base carried means pivotally supporting opposite ends of saidcarrier member, means operable to effect longitudinal adjustment of oneend of said carrier member relative to said base, upstandingindividually operable jacks carried by said base and extending in aseries lengthwise of said base and carrier member, the upper ends 0fsaid jacks engaging the under surface of said carrier member, and avacuum line having connection with said chuck members for effecting thegrip of the latter to the work.

5. A work holder comprising: an elongated flexible load supportingplate; individual means supporting the respective opposite ends of theplate; a row of jacks ar- 5 ranged lengthwise beneath the plateadjustably support ing that portion of the plate between the endsupporting means, and adapted to selectively vary the attitude of theplate and to support it in a selected attitude; and a row ofwork-retaining vacuum chuck members secured in iuxta- 10 posed relationalong the upper surface of said plate.

References Cited inthe file of this patent UNITED STATES PATENTS SemonJune 16, 1953

